keyscan.c

430单片机键盘扫描源码

#include "msp430x12x.h"
#include "KeyDefine.h"

extern unsigned int KeyHex;
extern short Error_Flag;

void KeyScan(void)
{
    short KeyMask,LoopCount,KeyCol,TestVal;
    KeyMask=1;
    LoopCount=5;
    KeyHex=0;
    P1OUT =P1OUT & 0x10;
    do
    {
        P3OUT &= 0xe0;
        P1DIR = 0xff;
        P1OUT &= 0x10;
        P1DIR = 0xf0;
        P3OUT |= KeyMask;
        TestVal=P1IN & 0x0f;
        if(TestVal)
        {
            KeyHex=KeyMask;
            KeyCol=P1IN & 0x0f;
            KeyHex += KeyCol << 8;
            LoopCount=1;
        }
        KeyMask = KeyMask <<1;
        LoopCount --;
    }while(LoopCount);
    if(KeyHex==0)
    {
        Error_Flag=NoKey;
    }
    P3OUT |=0x9f;
}